Systemic arterial supply to normal basilar segments of the left lower lobe: role of continuous thin sliced CT

A rare congenital anomaly of the left lower pulmonary artery is presented. A 39-year-old woman was admitted to our hospital for evaluation of a splenic mass. Abdominal CT disclosed abnormal vessels in the left lower lobe. Angiography revealed a large systemic artery from the descending aorta supplying the basilar segments of the left lower lobe. Continuous thin sliced CT revealed the anatomical details of this anomaly and showed that the tracheobronchial tree had a normal connection with the lung parenchyma. Although the volume of the left lower lobe was reduced, there were no symptoms related to this lesion. Since the splenic lesion was malignant lymphoma limited to the spleen, only splenectomy was performed. In spite of intensive systemic chemotherapy following the operation, there were no pulmonary complications. Although surgery may be necessary in the future, observation alone has been carried out for more than 3 years because of the lack of symptoms and normal pulmonary function. Continuous thin sliced CT was useful in evaluating this anomaly.